Dynamical, Strong-Field Gravity

该奖项支持相对论和相对论天体物理学的研究，并解决了NSF“宇宙之窗”大构想的优先领域。该项目的研究目标集中在理解爱因斯坦广义相对论的强场制度。这包括天体物理学和广义相对论的理论方面。在天体物理方面，主要工作是对双黑洞、黑洞-中子星和双中子星碰撞进行数值模拟。这对于支持引力波天文学的新兴领域非常重要。引力波天文学始于2015年，当时LIGO探测到了两个黑洞的碰撞。该领域的发展速度也令人惊叹，2017年首次探测到双中子星碰撞的引力波，同时大量观测天文学家对电磁波谱的后果进行了深入研究。需要这些事件的数值模型来帮助检测，并且对于破译发生的事情的细节至关重要。在理论方面，关于极端情况下时空的性质有许多悬而未决的问题。一个例子是爱因斯坦的理论所预言的发生在黑洞内部深处的奇点的本质。尽管由于没有信息可以从黑洞中逃脱，广义相对论在这里是如何崩溃的，但它仍然是一个令人感兴趣的理论，因为它将为一个假定的量子引力理论需要完成什么来解决经典奇点提供线索。这些项目将涉及研究生、本科生和博士后。他们将被训练去做领先的科学研究，成为在物理的相应领域的知识，并熟练的高性能计算和数值方法。这些技能对许多职业来说都是无价的，因此也将有利于并促进那些随后希望在学术界以外从事职业的学生和博士后的发展。将进行的引力波源建模项目的具体清单是：(1)了解中子星自旋在双中子星和黑洞-中子星合并中的后果；(2)开发检测高轨道偏心率合并的方法；(3)利用双黑洞碰撞中残余黑洞的准正态环落特性来检验广义相对论，特别是黑洞的唯一性。(4)在某些修正的引力理论中建立合并模型，以更好地理解观测如何能够排除这些修正的场景，或发现广义相对论之外的新物理。关于黑洞内部，最初的问题将是研究在三维渐近Anti - de-Sitter时空中引力坍缩期间形成的旋转BTZ （Banados-Teitelboim-Zanelli）黑洞的性质。与在四维时空中形成克尔黑洞相比，这提供了一个简化的场景，而克尔黑洞是这条研究路线的最终目标。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The research goals of this project are focused on understanding the strong-field regime of Einstein's theory of general relativity. This encompasses both astrophysical and theoretical aspects of general relativity. On the astrophysical side, the main effort is numerical simulation of binary black hole, black hole-neutron star and binary neutron star collisions. This is important to support the nascent field of gravitational wave astronomy that began in 2015 with LIGO's detection of the collision of two black holes. The speed at which the field is advancing is also breathtaking, with the first gravitational wave detection of a binary neutron star collision in 2017, accompanied by intense study of the aftermath across the electromagnetic spectrum by a large community of observational astronomers. Numerical models of such events are needed to aid in detection, and are crucial to decipher details of what happened. On the theoretical side, there are many outstanding questions about the nature of spacetime in extreme situations. One example is the nature of singularities predicted by Einstein's theory to occur deep in the interior of black holes. Though not thought to be observable as no information can escape from black holes, how general relativity breaks down here is still of keen theoretical interest, as it will give clues to what a putative theory of quantum gravity needs to accomplish to resolve classical singularities. The pursuit of these projects will involve graduate students, undergraduates and postdoctoral fellows. They will be trained to do leading scientific research, become knowledgeable in corresponding areas of physics, and adept in high-performance computing and numerical methods. These skills are invaluable to many professions, and would thus also benefit and further the development of those students and postdocs that subsequently wish to pursue careers outside academia.A specific list of gravitational wave source modeling projects that will be pursued are (1) understanding the consequences of neutron star spin in binary neutron star and black hole-neutron star mergers, (2) developing methods to detect mergers that occur with high orbital eccentricity, (3) using properties of the quasi-normal ringdown of the remnant black holes in binary black hole collisions to test general relativity, in particular the uniqueness properties of black holes, (4) developing models of mergers in certain modified gravity theories to better understand how observations can either rule out such modified scenarios, or detect novel physics beyond general relativity. Regarding black hole interiors, the initial problem will be to study the nature of rotating BTZ (Banados-Teitelboim-Zanelli) black holes formed during gravitational collapse in 3-dimensional asymptotically Anti de-Sitter spacetime. This offers a simplified scenario compared to forming Kerr black holes in four-dimensional spacetime, the ultimate goal of this line of research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.